A method and apparatus are disclosed for use with multiple input, multiple output (MIMO) signal processing techniques, which reduce the amount of memory and memory bandwidth used to store and access filter coefficients by compressing a filter coefficient based at least in part on one or more neighboring filter coefficients for storage and decompressing the filter coefficients when retrieved. The decompressed filter coefficients can be used with a MIMO filtering technique, and/or can be used to compress or decompress additional coefficients.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of storing filter coefficients for use with a multiple input, multiple output filter which reduce memory required to store the filter coefficients comprising: storing a first set of coefficients in memory, the first set corresponding to a first frequency bin; compressing a second set of coefficients corresponding to a second frequency bin, wherein compression of the second set of coefficients is based at least in part on the first set of coefficients; and storing the second set of coefficients.
2. The method of claim 1 , wherein compressing comprises calculating the difference, on a coefficient by coefficient basis, between the first set of coefficients and the second set of coefficients and quantizing the difference and only storing the difference as the second set of coefficients.
3. The method of claim 1 , wherein compressing comprises calculating the difference, on a coefficient by coefficient basis, between a true or approximate value of the first set of coefficients and the second set of coefficients, quantizing the difference and only storing the difference as the second set of coefficients.
4. The method of claim 3 , wherein a multiple input, multiple output filter processes signals over a large number of frequency bins in sequence in a DMT system, and compresses the corresponding filter coefficients in sequence.
5. The method of claim 1 , further comprising; compressing a third set of coefficients corresponding to a third frequency bin, wherein compression of the third set of coefficients is based at least in part on the second set of coefficients; and storing the third set of coefficients.
6. The method of claim 5 , wherein compressing comprises determining a difference, on a coefficient by coefficient basis, between the third set of coefficients and any function or combination of one or more prior coefficients.
7. A method of accessing filter coefficients for use with a multiple input, multiple output filter comprising: retrieving a set of first coefficients from memory; sequentially retrieving, on a bin by bin basis in a DMT system, a compressed set of second coefficients from memory, wherein the compressed set of second coefficients are stored in a compressed form; and decompressing the compressed set of second coefficients based at least in part on the set of first coefficients and the compressed sets of second coefficients to create a set of second coefficients.
8. The method of claim 7 , wherein decompressing comprises adding, on a coefficient by coefficient basis, the set of first coefficients to the compressed set of second coefficients.
9. The method of claim 7 , further comprising retrieving a compressed set of third coefficients from memory, wherein the compressed set of third coefficients are stored in a compressed form; and decompressing the compressed set of third coefficients based at least in part on the set of second coefficients and the compressed sets of third coefficients to create a set of third coefficients.
10. A method of filtering using a multiple input, multiple output filter comprising: receiving two or more unfiltered signals for filtering by a multiple input, multiple output filter; retrieving a set of coefficient prediction error values from a memory, each of which corresponds to a filter coefficient for use in filtering a set of input signals in the frequency domain; generating a set of filter coefficients using the retrieved coefficient prediction error values; filtering the two or more unfiltered signals using the generated set of filter coefficients within the multiple input, multiple output filter to create two or more filtered signals; and outputting the two or more filtered signals form the multiple input, multiple output filter.
11. The method of claim 10 , further comprising processing the two or more filtered signals from the multiple input, multiple output filter to create two or more processed signals and transmitting the two or more processed signals over two or more channels to a remote terminal.
12. The method of claim 10 , further comprising retrieving at least one filter coefficient upon which the set of filter coefficients are generated using the retrieved prediction error values.
13. The method of claim 10 , wherein an amount of memory consumed by the set of coefficient prediction error values is less than an amount of memory consumed by the set of filter coefficients generated using the retrieved prediction error values.
14. The method of claim 10 , wherein generating a set of filter coefficients using the retrieved coefficient prediction error values is accomplished via passing the coefficient prediction error values through a prediction filter.
15. The method of claim 10 , wherein the method reduces the amount of data which must be retrieved from memory.
16. A filter coefficients storage and access system for use with a multiple input, multiple output filter comprising: a storage subsystem configured to store a first set of coefficients in memory, the first set corresponding to a first frequency bin, and one or more additional values related or representing compressed coefficients; an interface coupled to the storage subsystem and the multiple input, multiple output filter, the interface configured to: retrieve the first set of coefficients from the storage subsystem; provide the first set of coefficients to the multiple input, multiple output filter; retrieve one or more additional values from the storage subsystem; process the additional values and the first set of coefficient to create a second set of coefficients corresponding to a second frequency bin; and provide the second set of coefficient to the multiple input, multiple output filter.
17. The system of claim 16 , further comprising a controller configured to coordinate timing between the interface and the multiple input, multiple output filter.
18. The system of claim 16 , wherein processing comprises adding the additional values to the first set of coefficients.
19. The system of claim 16 , wherein processing comprises decompressing.
20. The system of claim 16 , wherein the interface further comprises communication paths between the storage subsystem and the interface.
21. A system for multiple input, multiple output filtering using coefficients, the system comprising: a storage subsystem comprising a memory storing a set of coefficient prediction error values, each of which corresponds to a filter coefficient for use in filtering a set of input signals in the frequency domain; a filtering subsystem coupled to the storage subsystem comprising: an interface configured to retrieve the prediction error values from memory and to generate a set of filter coefficients using the retrieved prediction error values, wherein the filtering subsystem is configured to filter the input signals using the generated set of filter coefficients.
22. The system of claim 21 , wherein generating the set of filter coefficients comprises decompressing the prediction error values.
23. The system of claim 21 , wherein generating the set of filter coefficients comprises adding the prediction error values to another filter coefficient.
24. The system of claim 21 , wherein the interface is separate from the filtering subsystem and is further configured to receive timing information from the filtering subsystem to coordinate the generating of filter coefficients and sending of filter coefficient to the filtering subsystem.
25. The system of claim 21 , wherein the interface further comprises a quantizer configured to compress the prediction error values.
26. The system of claim 21 , further comprising a training and adaptation module configured to update coefficient values and generate updated coefficient prediction error values for storage in the storage subsystem.
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January 25, 2008
December 4, 2012
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